Redmine

After Model plugin creation I tryed to create a new instance of rplugin model with the following error in Rails Console:

ActiveRecord::DangerousAttributeError: errors is defined by Active Record. Check to make sure that you don't have an attribute or method with the same name.

I chaged all most three times the Plugin and Model name without luck, I am following the Redmine Plugin Development guide step by step but something is wrong.

Environment Info:

Environment:
  Redmine version                3.0.0.stable.14044
  Ruby version                   2.1.5-p273 (2014-11-13) [x86_64-linux]
  Rails version                  4.2.0
  Environment                    development
  Database adapter               PostgreSQL
SCM:
  Subversion                     1.8.10
  Git                            2.1.0
  Filesystem                     
Redmine plugins:
  no plugin installed